There exist on the market machines for automatic manipulation of toxic substances, comprising: a magazine for containers, such as sacs, flasks and the like, each provided with a mouth closed by a respective cap made of perforable material and containing substances necessary for the preparation of drugs; a dosage station, present in which is at least one seat designed to withhold a corresponding syringe of a commercial type; and an anthropomorphic robot provided with a gripping head for picking up a container from the magazine, transferring it to the dosage station at a point corresponding to a syringe, and approaching it to the needle of the syringe in such a way that the needle, by perforating the cap, penetrates into the container to be able to inject therein or draw therefrom a substance. In addition, provided in these machines is an optical sensor of the photocell type for facilitating axial alignment of the mouth with the needle of the syringe.
The main drawback of such machines is a considerable difficulty in aligning containers having a mouth of small dimensions on account of the low level of precision with which the sensor detects the position of the tip of the needle. Very frequently, in fact, a terminal portion of the needle can be curved on account of production faults or damage caused by the operations of storage and/or transport, and a small dimension of the mouth frequently renders impossible proper alignment and, hence, insertion of the needle in the container.